Group Captive Solar in India: Complete Guide for 2025

Key Takeaways

• Group captive solar is the most cost-effective open access model, saving 35–55% on industrial electricity by waiving the cross-subsidy surcharge (CSS).
• You invest just 26% equity in a solar plant and consume at least 51% of the power — in return, you're treated as a captive consumer with zero CSS.
• The all-in cost of group captive solar power ranges from ₹4.0–6.5/kWh across major Indian states, compared to grid tariffs of ₹7.5–13.0/kWh.
• This model is ideal for large industrial consumers (1 MW+ demand) who want off-site solar without the full CAPEX investment of building their own plant.
• Sun Wave Technologies structures group captive arrangements for industrial clients across Delhi-NCR, Haryana, Rajasthan, and North India.

What Is Group Captive Solar Power?

Group captive power is a legal framework under the Indian Electricity Act, 2003, that allows multiple industrial consumers to jointly own a power plant and consume its output as "captive consumers." When applied to solar, it creates a powerful cost-reduction mechanism:

The core principle: If you invest 26% equity in a solar plant and consume 51% of its output, you're classified as a captive consumer. Captive consumers are exempt from the cross-subsidy surcharge (CSS), which saves ₹1–2.5/kWh — the single biggest cost component in open access solar procurement.

How Group Captive Differs from Other Solar Models

Group captive sits in the sweet spot — partial investment for significantly lower power costs than third-party open access, with access to MW-scale solar beyond what your rooftop can accommodate.

The Legal Framework: 26% + 51% Rule

The Electricity Rules, 2005 (amended) define captive generating plant requirements:

Rule 3: Captive Status Requirements

1. Equity requirement: The captive consumer(s) must hold not less than 26% of the ownership of the generating plant
2. Consumption requirement: The captive consumer(s) must consume not less than 51% of the aggregate electricity generated in any financial year

How the 26% Equity Works in Practice

For a 10 MW group captive solar plant costing ₹35 Crore:

• Total equity: ₹10 Crore (assuming 70:30 debt-equity ratio)
• 26% captive equity: ₹2.6 Crore
• Your share (for 2 MW allocation): ₹52 lakhs (26% × 2/10)

This ₹52 lakh equity investment gives you access to 2 MW of solar power at CSS-exempt rates, saving ₹30–50 lakhs per year. The ROI on the equity investment alone exceeds 50%.

Multiple Consumers in One Plant

A group captive plant can have multiple equity investors:

The key constraint: all captive consumers must collectively hold at least 26% equity and consume at least 51% of total generation.

The CSS Waiver: Why It Matters So Much

The cross-subsidy surcharge (CSS) is a charge levied on open access consumers to compensate DISCOMs for revenue lost when you buy power from sources other than them. CSS rates across major states:

In Maharashtra, the CSS waiver alone saves ₹34.7 lakhs per MW per year. Over 25 years, that's nearly ₹8.7 Crore per MW — just from the CSS exemption.

State-Wise Group Captive Economics

Haryana Group Captive Solar

• Grid tariff: ₹8.5–10.0/kWh (HT industrial)
• Solar PPA rate: ₹3.0–3.5/kWh
• Transmission charges: ₹0.77/kWh
• CSS: ₹0 (waived for group captive)
• Additional surcharge: ₹0.91/kWh
• Wheeling charges: ₹0.37/kWh
• All-in cost: ₹5.0–5.6/kWh
• Savings: 40–50% vs. grid tariff

Rajasthan Group Captive Solar

• Grid tariff: ₹7.5–9.0/kWh
• Solar PPA rate: ₹2.8–3.3/kWh
• Transmission charges: ₹0.63/kWh
• CSS: ₹0 (waived)
• All-in cost: ₹4.2–5.0/kWh
• Savings: 40–50%

Rajasthan offers the best group captive economics in India due to low transmission charges and the highest solar irradiance (5.5–6.0 kWh/m²/day).

Maharashtra Group Captive Solar

• Grid tariff: ₹10.0–13.0/kWh
• Solar PPA rate: ₹3.0–3.5/kWh
• Transmission charges: ₹1.08/kWh
• CSS: ₹0 (waived — this alone saves ₹2.39/kWh)
• All-in cost: ₹5.0–6.0/kWh
• Savings: 50–55%

Maharashtra's combination of very high grid tariffs and very high CSS makes group captive the most impactful solar procurement option.

Gujarat Group Captive Solar

• Grid tariff: ₹7.5–8.5/kWh
• Solar PPA rate: ₹2.8–3.2/kWh
• All-in cost: ₹4.0–5.0/kWh
• Savings: 40–50%

Gujarat's low CSS (₹0.87/kWh) means third-party open access is also viable, but group captive still saves an additional ₹12.6 lakhs per MW per year.

Setting Up a Group Captive Solar Arrangement

Step 1: Assess Your Eligibility

• Minimum contracted demand: 1 MW (state-dependent; some allow 500 kW)
• Connection type: HT (High Tension) — typically 11 kV or above
• No outstanding DISCOM dues
• Stable consumption pattern: Predictable daytime load for accurate power scheduling

Step 2: Find a Developer or SPV

You can either:

• Join an existing group captive SPV: A developer has already built or is building a solar plant and is looking for equity partners. This is the fastest route.
• Form a new group captive SPV: Multiple industrial consumers form a Special Purpose Vehicle (SPV) and commission a solar developer to build the plant.

Sun Wave Technologies facilitates both approaches for industrial clients in North India.

Step 3: Structure the Equity

The equity structure must satisfy the 26% rule:

• Direct equity: You invest cash into the SPV and receive shares
• Equity amount: Typically ₹20–60 lakhs per MW of power allocation
• Equity returns: You earn dividends from the SPV's operations (typically 8–12% IRR on equity)
• Lock-in period: Usually 5–7 years before you can exit the equity position

Step 4: Sign the PPA

The group captive PPA is between your company and the SPV:

• PPA rate: ₹2.8–3.5/kWh (solar generation cost)
• Tenure: 20–25 years
• Performance guarantees: Minimum generation commitments
• The PPA rate does NOT include transmission and wheeling charges — those are paid separately to the DISCOM

Step 5: Apply for Open Access

• Submit long-term open access application to the State Load Dispatch Centre (SLDC)
• Provide proof of 26% equity holding and group captive status
• Obtain connectivity approval from the transmission utility
• Timeline: 60–120 days

Step 6: Commission and Start Consuming

• Solar plant is commissioned by the developer
• Power scheduling begins with the SLDC
• You receive monthly bills: PPA cost (from SPV) + transmission charges (from DISCOM)
• Net savings begin immediately

Group Captive vs. Rooftop Solar: The Combined Strategy

The best approach for large industrial consumers is to combine both models:

Rooftop solar gives you the cheapest per-unit cost (no transmission charges). Group captive OA gives you scale beyond your roof's capacity. Together, they maximize total savings.

Risks and Mitigation in Group Captive Solar

Risk 1: Regulatory Changes

State governments periodically revise open access charges and CSS rates.

Mitigation: Long-term open access agreements (10–25 years) typically grandfather the charges applicable at the time of the agreement. Verify this protection in your OA application.

Risk 2: Developer Default

If the developer fails to maintain the solar plant, generation drops.

Mitigation: The SPV structure means the plant is a separate legal entity. Include step-in rights in the SHA (Shareholder Agreement) that allow captive consumers to replace the developer's O&M team.

Risk 3: Co-Consumer Default

If another equity partner exits or defaults on consumption commitments, the group captive status could be jeopardized.

Mitigation: Ensure the SHA has clear exit provisions requiring the departing consumer to sell their equity to a replacement consumer within 90 days. Include cross-default clauses.

Risk 4: Captive Status Disqualification

If the 26% equity or 51% consumption test is not met in any financial year, you lose captive status and must pay full CSS retrospectively.

Mitigation: Over-allocate consumption to ensure 51% is met even with seasonal variations. Monitor quarterly and adjust scheduling if needed.

Risk 5: Equity Lock-In

Your equity investment is illiquid for the lock-in period (5–7 years).

Mitigation: The equity amount is typically small (₹20–60 lakhs per MW) relative to the annual savings (₹30–50 lakhs per MW). The investment recovers in 1–2 years through CSS savings alone.

Tax Benefits of Group Captive Solar

Accelerated Depreciation on Equity

Your 26% equity investment in the SPV qualifies for accelerated depreciation benefits:

• The SPV (which owns the solar plant) can claim 40% AD on the plant cost
• This flows through as higher dividends or lower PPA rates for equity holders
• Consult your tax advisor on the optimal structure for maximizing AD benefits

Operating Expense Deduction

PPA payments and open access charges are fully deductible as operating expenses, reducing your taxable income.

RPO Compliance

Group captive solar consumption counts toward your Renewable Purchase Obligation (RPO), avoiding the need to purchase RECs (₹1–2/kWh) separately.

Frequently Asked Questions

What is the minimum investment for group captive solar?

The minimum equity investment depends on the plant size and your power allocation. Typically, for 1 MW of power allocation from a 10 MW plant, you'd invest ₹25–60 lakhs (26% of your proportional equity share). This is a one-time investment that unlocks CSS-free solar power for 20–25 years, saving ₹25–50 lakhs per year. The equity pays for itself within 1–2 years.

How much can I save with group captive solar compared to regular open access?

The primary advantage of group captive over third-party open access is the CSS waiver. This saves ₹0.87–2.39/kWh depending on your state — translating to ₹12.6–34.7 lakhs per MW per year. Over 25 years, the CSS waiver alone is worth ₹3–9 Crore per MW. After including all charges, group captive solar costs ₹4.0–6.5/kWh vs. ₹5.5–9.0/kWh for third-party open access.

Can small factories participate in group captive solar?

Yes, though the minimum contracted demand for open access (typically 1 MW) limits participation. Factories with 500 kW–1 MW demand in some states can participate. For smaller factories, rooftop solar with net metering is more practical. Some developers are creating group captive structures specifically for SME clusters where multiple small factories share a solar plant.

What happens to my equity if I want to exit the group captive arrangement?

Exit provisions are defined in the Shareholder Agreement (SHA). Typically, after the lock-in period (5–7 years), you can sell your equity to another industrial consumer at fair market value. Some SHAs include a put option allowing you to sell back to the developer at a pre-agreed price. The key requirement is that the new buyer must also be an eligible captive consumer to maintain the group's captive status.

Is group captive solar better than rooftop RESCO?

It depends on your situation. Rooftop RESCO (₹3.5–5.5/kWh) is cheaper per unit because there are no transmission charges. However, rooftop capacity is limited by your roof area. Group captive (₹4.0–6.5/kWh) gives you access to MW-scale power beyond your rooftop limit. The best strategy combines both: maximize rooftop solar first, then use group captive for additional requirement.

How is group captive solar different from a regular solar PPA?

A regular solar PPA for on-site (rooftop) installation doesn't involve equity investment or open access charges — the developer installs on your roof and sells you power directly. A group captive PPA involves 26% equity investment in an off-site solar plant, open access charges (transmission, wheeling), but critically eliminates CSS. The economic comparison depends on your state's CSS rate and available rooftop space.